Evaluation of the Properties of Asphalt Concrete Modified with Crumb Rubber Using Marshall Test

Abstract

This study examines the properties of asphalt concrete modified with crumb rubber using Marshall test. In this study, 5 different mixtures containing 3, 5, 7, 9 and 11% crumb rubber by total mix were considered. The Marshall samples were prepared, tested in the Marshall stability and flow equipment and analysed. The results from the Marshall tests indicate that the stability of the asphalt concrete increases with increasing bitumen content up to 6.2% bitumen content with the mixture containing 7% crumb rubber having the highest stability. The flow initially increased with the addition of crumb rubber up to 7%, but decreased gradually as the percentage of the crumb rubber was further increased to 9 and 11%. Generally, the study indicates that crumb rubber can be used to modify typical asphalt concrete used in Nigeria. This implies that economic gains could be derived by generating wealth from the use of discarded tyre and job creation for those who will be responsible for collecting and processing the discarded tyres and construction of roads that will stand the test of time. Also, successful utilisation will solve the problem of disposing the tyres.